Biomedical subjects

N Roos

Publications and source records attributed to N Roos.

At least 37 records · Page 2Linked to original sources

PubMed1999

Helical CT of pulmonary nodules in patients with extrathoracic malignancy: CT-surgical correlation.

OBJECTIVE: Our aim was to assess the sensitivity of helical CT for revealing pulmonary nodules. Thoracotomy with palpation of the deflated lung, resection, and histologic examination of palpable nodules was used as the gold standard. SUBJECTS AND METHODS: Thirteen patients underwent helical CT (slice thickness, 5 mm; reconstruction intervals, 3 mm and 5 mm; interpreted by two independent observers). Subsequently, patients underwent unilateral (n = 6) or bilateral (n = 7) surgical exploration, and CT-surgical correlation of 20 lungs was performed. RESULTS: Ninety nodules were resected (61 were smaller than 6 mm; 13 were 6-10 mm; 11 were larger than 10 mm; in five nodules, the size was not recorded at surgery). Sixty-nine nodules were located in the pulmonary parenchyma and 21 in the visceral pleura. Of the 90 lesions, 43 (48%) were found on histology to represent metastases. For lesions detected by at least one observer, the sensitivity of helical CT was 69% for intrapulmonary nodules smaller than 6 mm, 95% for intrapulmonary nodules larger than or equal to 6 mm, and 100% for histologically proven intrapulmonary metastases larger than or equal to 6 mm. For lesions smaller than or equal to 10 mm, sensitivity was better using a reconstruction interval of 3 mm rather than of 5 mm. CONCLUSION: In this study, the sensitivity of helical CT exceeded the sensitivity of conventional CT in previous reports. However, because of limitations in the detection of intrapulmonary nodules smaller than 6 mm and of pleural lesions, complete surgical exploration should remain the procedure of choice in patients undergoing pulmonary metastasectomy. Preoperative helical CT should be used to guide the surgeon to lesions that are difficult to palpate.

Adult↗

PubMed1999

Early empiric antifungal therapy of infections in neutropenic patients comparing fluconazole with amphotericin B/flucytosine.

We compared the efficacy and tolerability of fluconazole (FCA) with amphotericin B/flucytosine (ABF) in neutropenic patients with haematological malignancies. Antifungal therapy started on day 4 when fever was unresponsive to antibiotics or on day 1 together with the antibiotics, if there was evidence of mycosis. If patients did not respond to FCA after 7 days they switched to ABF. 98 patients, 51 FCA and 47 ABF were included in the study. Response to fever was achieved in 28/51 FCA patients and in another 16 after switching to ABF. So in overall 44/51 (86.2%) of the FCA and 37/47 (78.8%) of the ABF group defervescence was observed. 46 patients (21 FCA, 25 ABF) developed radiological signs of pneumonia. Resolution of infiltrates was achieved in 5/21 FCA and 20/25 ABF patients, and another 10 of 15 initially not responding patients showed regression when switched to ABF, 5 of these had highly suspected aspergillosis. Adverse events occurred in 19.6% of FCA and 97.9% of ABF patients. In conclusion fluconazole and amphotericin B/flucytosine seem to be equally effective. In view of its lower toxicity fluconazole may be preferred as first line empiric antifungal agent, but in case of nonresponse, pneumonia or aspergillosis it may be replaced by amphotericin B combined with flucytosine.

Adolescent↗

PubMed1998

Endocytosed ricin and asialoorosomucoid follow different intracellular pathways in hepatocytes.

Earlier studies have suggested that fluid phase endocytosis in rat hepatocytes takes place via a clathrin-independent mechanism [1,2]. This observation suggests that a relatively large amount of plasma membrane outside coated pits may be involved in hepatic endocytosis. Ricin, which binds to galactose residues on glycoproteins and glycolipids, has, in this report, been used as a general marker for the plasma membrane of hepatocytes. The endocytosis of ricin was compared with that of asialoorosomucoid (AOM) which is taken up exclusively via clathrin-coated pits. Hypertonic medium has been shown to inhibit uptake via coated pits more effectively than clathrin-independent uptake [3-5]. It was found, in this study, that the addition of 100 mM sucrose to the incubation medium inhibited the uptake of 125I-tyramine-cellobiose-asialoorosomucoid (125I-TC-AOM) more extensively than that of 125I-tyramine-cellobiose-ricin (125I-TC-ricin), compatible with the notion that the two probes are internalised via different mechanisms. Subcellular fractionation experiments indicated that 125I-TC-ricin entered a denser endocytic organelle than that receiving 125I-TC-AOM. To determine whether the separation of the two probes was due to a different transport kinetics (i.e. that 125I-TC-ricin is transported more rapidly to a later, denser compartment than 125I-TC-AOM) the cells were incubated at 18 degreesC to allow a slower internalisation/transport of the labelled probes. The results obtained showed, again, that the early endosomes containing 125I-TC-ricin were significantly denser than those containing 125I-TC-AOM. We also employed the horseradish peroxidase (HRP)-diaminobenzidine (DAB) density shift technique of Courtoy et al. [6] to determine whether 125I-TC-ricin and 125I-TC-AOM were in separate endosomes early after their uptake. The results showed that early endosomes containing 125I-TC-AOM were density shifted whereas those containing 125I-TC-ricin were unaffected by the density shift procedure. The use of probes labelled with 125I-TC allowed us to identify compartments involved in the degradation of 125I-TC-AOM and 125I-TC-ricin, by measuring acid soluble radioactivities in the gradient fractions. It was found that 125I-TC-ricin was degraded mainly in endosomes, whereas 125I-TC-AOM, as expected, was degraded mainly in lysosomes.

Animals↗

PubMed1998

Crosslinking of sodium caseinate by a microbial transglutaminase.

Sodium caseinate is an effective substrate for transglutaminase. Crosslinking takes place at fast reaction rates resulting in high degrees of crosslinking. The polymers can be hydrolysed by trypsin, but the proteolysates contain residual portions of non- or partlyhydrolysed aggregates. Crosslinking of hydrolysed sodium caseinate decreased the number of free amino groups, but leads only to a very small increase in molecular weight of the peptides.

Caseins↗

PubMed1998

A case of severe cerebral trauma in a patient under chronic treatment with cyclosporine A.

A case of severe cerebral head injury in a child, chronically treated with cyclosporine A after orthotopic liver transplantation, is presented. The initial Glasgow Coma Scale score after the motor vehicle accident was 3, and computed tomography showed multiple sites of intracerebral bleeding, an epidural hematoma, and signs of perifocal edema. Although these lesions are normally associated with a poor outcome, the child recovered unexpectedly well. In brain injury, a lucid interval can be followed by secondary neurologic deterioration due to a loss of high-energy metabolites, a release of neurotransmitters, and an increase in intracellular Ca2+. These events finally led to cell damage in the penumbra of an ischemic infarction. Among other drugs, immunosuppressants such as cyclosporine A have been shown to exhibit neuroprotective properties in experimental models if given during this time interval of secondary neurologic deterioration. Although human data on these effects are still lacking, we conclude that neuroprotective actions of cyclosporine A may have been involved in the favorable outcome in this 14-year-old boy.

Adolescent↗

PubMed1997

Amino acid utilization and isotope discrimination of amino nitrogen in nitrogen metabolism of rat liver in vivo.

Urea and plasma protein differ in natural 15N abundance up to 10%. The origin of this difference is the branched nitrogen metabolism in the liver. One main branch is the protein synthesis pathway, the other the urea synthesis pathway. By this branching 15N of precursor amino acids is depleted in urea while it is enriched in protein. With the 15N abundance of precursor amino acids, which may be taken from jejunum tissue, utilization of amino acids in liver metabolism can be calculated from isotope discrimination in either pathway. This was investigated by feeding different proteins to rats. When feeding high quality protein (whey protein) utilization of amino acids in liver metabolism at requirement intake was better than at zero protein intake (> 85% vs. 70%). From this we conclude that the pattern of amino acids available from the metabolic pool at zero protein intake is characterized by an imbalance. This endogenous imbalance can be complemented by exogenous dietary amino acids so that nitrogen excretion may even be smaller than the so-called "obligatory" losses of intakes not exceeding requirement. Thus, the quality of dietary protein is reflected not only by N balance. It also may be quantified by analysis of isotope discrimination in nitrogen metabolism of the liver. In addition, the quality of amino acid pattern available from the metabolic pool is indicated by this method.

Amino Acids↗

PubMed1997

Storage of vitamin A in extrahepatic stellate cells in normal rats.

In mammals, vitamin A is primarily stored as retinyl esters in hepatic stellate cells under normal dietary intake of the vitamin. Previously, extrahepatic vitamin A-storing stellate cells have only been identified in animals maintained on a vitamin A-rich diet, and it has not been known whether these cells play a role in normal vitamin A metabolism. The purpose of this study was, to quantify the stellate cell lipid droplet area in hepatic and extrahepatic stellate cells in control rats and in rats fed excess vitamin A. The stellate cells were identified by the gold chloride staining technique, specific autofluorescence of retinyl ester, and by electron microscopy. The stellate cell lipid droplet area was then quantitated by the use of morphometric quantitation. We demonstrated that lipid droplet-containing stellate cells were identified in liver, lung, kidney, and intestine, in normal as well as vitamin A-fed rats. The area of lipid droplets in liver, lung, and intestine stellate cells of normal rats was 0.2, 0.3, and 0.04 mm2 per cm2 tissue, respectively. When the rats were administered excess vitamin A, the hepatic, lung, and intestinal stellate cell lipid droplet area increased about 10-fold, 2-fold, and 40-fold, respectively. Thus the present study shows that extrahepatic stellate cells in lung and intestine of normal rats contain lipid droplets, and that these lipid droplets increase in area when high doses of vitamin A are fed to the animals. These data suggest that not only liver stellate cells but also extrahepatic stellate cells play an important role in vitamin A storage in normal as well as vitamin A-fed animals.

Actins↗

PubMed1996

How many general surgeons do you need in rural areas? Three approaches to physician resource planning in southern Manitoba.

OBJECTIVE: To assess critically the results of using three different approaches to planning for the number of general surgeons in rural areas. DESIGN: Estimates of the number of general surgeons needed using a ratio approach, a and a population-needs-based approach. SETTING: Rural southern Manitoba. OUTCOME MEASURE: Number of general surgeons needed. RESULTS: The ratio approach supported the recruitment of 7.8 to 14.5 additional general surgeons to rural southern Manitoba. The repatriation approach suggested that the area might support five additional general surgeons, if residents could be persuaded to undergo their surgery closer to home. The population-needs-based approach suggested that the health status of area residents was similar to that of residents of other areas of the province and that they had a higher rate of surgery than residents of other areas; no additional surgeons were apparently needed. CONCLUSIONS: Each method has certain advantages, and none is necessarily useful in isolation. Hence, the most effective approach to planning for general surgeons is likely a combination of all three methods. Other factors that may be important include the type of payment structure and the need for professional groups to monitor variations in rates of surgery.

Aged↗

PubMed1996

A novel immunogold cryoelectron microscopic approach to investigate the structure of the intracellular and extracellular forms of vaccinia virus.

We introduce a novel approach for combining immunogold labelling with cryoelectron microscopy of thin vitrified specimens. The method takes advantage of the observation that particles in suspension are concentrated at the air-water interface and remain there during the subsequent immunogold labelling procedure. Subsequently, a thin aqueous film can be formed that is vitrified and observed by cryoelectron microscopy. In our view, a key early step in the assembly of vaccinia virus, the formation of the spherical immature virus, involves the formation of a specialized cisternal domain of the intermediate compartment between the endoplasmic reticulum and the Golgi. Using this novel cryoelectron microscopy approach, we show that in the intracellular mature virus (IMV) the core remains surrounded by a membrane cisterna that comes off the viral core upon treatment with dithiothreitol, exposing an antigen on the surface of the viral core. Complementary protease studies suggest that the IMV may be sealed not by membrane fusion but by a proteinaceous structure that interrupts the outer membrane. We also describe the structure and membrane topology of the second infectious form of vaccinia, the extracellular enveloped virus, and confirm that this form possesses an extra membrane overlying the IMV.

Chemical Phenomena↗

PubMed1996

[Bronchiolitis obliterans with organizing pneumonia: differential diagnosis of pneumonia refractory to antibiotics].

HISTORY AND FINDINGS: A previously healthy 58-year-old woman was admitted with rapidly worsening dyspnoea, dry cough and subfebrile temperature. Chest radiogram showed spotty infiltrations, especially in the bases of both lungs. She was dyspnoic with mild tachypnoea (24/min) and mild cyanosis of the lips. Fine, non-resonant rales were heard over the middle and lower lobes bilaterally. INVESTIGATIONS: Erythrocyte sedimentation rate was markedly raised (97/110 mm), arterial oxygen partial pressure slightly decreased (45 mm Hg), CO2 partial pressure was 32 mm Hg. Bronchoalveolar lavage was unremarkable. TREATMENT AND COURSE: Because of the respiratory impairment broad antibiotic treatment was at once commenced empirically with gentamycin, cefotaxim, erythromycin, rifampicin and fluconazole. As the response was poor, a transbronchial lung biopsy was performed. This merely showed nonspecific lymphoplasmacellular bronchitis. An open biopsy then revealed bronchiolitis obliterans with organizing pneumonia (BOOP). Treatment with initially 75 mg prednisone daily quickly brought about improvement and the patient was entirely well after 6 months. CONCLUSION: The described constellation of history and clinical as well as radiological findings should strongly suggest BOOP. With adequate treatment the prognosis is excellent.

Anti-Bacterial Agents↗

PubMed1996

[Low dose computerized tomography of the thorax. Experimental and clinical studies].

INTRODUCTION: Computed tomography is a significant source of medical radiation exposure for populations in Europe. Reduced radiation exposure may be possible with modern CT scanners with an image quality that while less good than before remains acceptable for clinical purposes. The lung appears particularly well suited to investigation with low-dose CT owing to the high contrast between normal and diseased pulmonary parenchyma. METHODS: We analysed the diagnostic accuracy of different low-dose CT protocols for the detection of pulmonary nodules using inflation-fixed isolated postmortem lung specimens in a chest phantom. In a comparative patient study diagnostic accuracies of standard-dose CT (120 kV, 250 mAs; slice thickness 10 mm, pitch 1) and low-dose CT (120 or 140 kV, 50 mAs; slice thickness 5 or 10 mm, pitch 1 or 2) were assessed. RESULTS: Preliminary results suggest that low-dose CT protocols with radiation exposure of 10-20% of that with standard-dose CT an reliably depict soft tissue density pulmonary nodules with a diameter of more than 5 mm and can also demonstrate smaller nodules equally well is many cases. CONCLUSIONS: Low-dose CT may frequently be an adequate imaging procedure in a given clinical setting, particularly in young patients with benign disease.

Humans↗

PubMed1996

[Radiation exposure in low dose computerized tomography of the thorax].

Computed tomography accounts for a high percentage of the populations exposure to radiation. Every possible means of reducing patient exposure must be considered. Exposure reduction will be most appropriate for organs with large absorption differences, since the accompanying decrease in signal-to-noise ratio will have a smaller effect. It has been shown in the literature that high-contrast details in the lung can be depicted, even with the lowest exposure rates. Therefore, experimental data are presented by means of thermoluminescence dosimetry and calculations using conversion factors to determine the technical parameters to be adopted for achieving the effective equivalent dose close to that of a conventional chest X-ray in two projections. With helical CT (pitch 2, 50 mAs, 120 kV, 5-mm slice thickness) it was possible to reduce the equivalent dose from 9.6 mSv to 0.6 mSv, which is comparable with the exposure in a conventional chest X-ray, measured to be 0.2 mSv.

Equipment Design↗

PubMed1996

[Appearance forms of mesenteric cyst. A case report].

Mesenteric cysts are considered as a rare cause of abdominal complaints. Histologically, several specific types can be distinguished: lymphangioma, nonpancreatic pseudocyst, enteric duplication cyst, enteric cyst and mesothelial cyst. Histopathological classification and radiological findings in two cases of mesenteric cysts are presented, and, with regard to the literature, radiological appearance and differential diagnoses are discussed.

Adult↗

PubMed1996

[Phenomenology of pulmonary HRCT. Definitions, differential diagnosis and clinical relevance].

High-resolution computed tomography (HRCT) has proved to be the imaging technique of choice for the lung in numerous studies, allowing precise depiction of normal pulmonary anatomy-including the lobular architecture-as well as relevant pathologic changes. Its sensitivity, specificity and accuracy in this respect are markedly superior, not only to chest radiography, but also to conventional CT. Guidelines for standardized assessment and interpretation of HRCT findings have not been established in the German literature. The purpose of this paper was to develop a systematic classification of pulmonary HRCT findings based on the appearance of morphologic abnormalities (descriptive classification) and their relationship to anatomic structures of pulmonary parenchyma (anatomic classification). Reticular, nodular, and non-reticular/non-nodular densities, as well as lucencies, can be differentiated. Abnormalities of the pleural space are discussed separately. Following the presentation of typical CT findings, morphologic correlation and differential diagnosis are discussed. In addition, we point out indications and specific features of the clinical value of the technique.

Diagnosis, Differential↗

PubMed1996

[Diagnostic imaging in bronchiectases. Value of CT and HRCT].

Various diseases can cause bronchiectasis as a result of inflammatory bronchial wall damage. The diagnosis is based on imaging techniques, which are also required to assess the extent and localization of dilated bronchi and possible causes. Chest radiography only occasionally allows the diagnosis of bronchiectasis (Fig.2) and is usually not a sufficient basis for therapeutic decisions (Fig. 1a), but it is important for follow-up studies. Bronchography (Fig.1b) was considered the diagnostic procedure of choice in suspected bronchiectasis for decades. Being an invasive procedure, it has recently been almost completely replaced by computed tomography (CT), which can also demonstrate associated pulmonary abnormalities (Fig.6) in addition to visualizing the bronchi. CT diagnosis of bronchiectasis is based on the demonstration of bronchial dilatation relative to the adjacent pulmonary artery (Figs. 4, 5, 7-9), lack of bronchial tapering (Figs. 3, 4, 10) and visualization of bronchi in the lung periphery (Figs. 3, 5, 8, 10). In suspected bronchiectasis high-resolution scans should be obtained during inspiration. Contiguous, thicker slices or scans taken during expiration may be required in particular cases.

Bronchiectasis↗

PubMed1996

[Bronchiolitis obliterans with organizing pneumonia (BOOP). Clinical aspects, pathology and radiologic images].

Bronchiolitis obliterans with organizing pneumonia (BOOP) is a clinicopathological syndrome of unknown etiology. Histopathologically, it is characterized by plugs of fibroplastic connective tissue within respiratory bronchioles, mononuclear cell infiltrates in parenchyma adjacent to the affected bronchioles and foam cells within alveolar air-spaces. The disease usually presents as a subacute illness with complete resolution. A subset of BOOP, however, is associated with a fulminant course and a high lethality due to respiratory failure. Early diagnosis and therapy are mandatory. Chest radiography, computed tomography (CT), bronchoalveolar lavage (BAL) and open lung biopsy are the primary diagnostic techniques. Radiographically, BOOP is characterized by patchy areas of consolidation that are usually bilateral, peripheral and often migratory. In some cases small, round opacities may be observed as the only abnormality. CT can show the pattern of ground glass opacities, areas of airspace consolidation and small, round opacities, while considerable fibrotic change is usually not seen. A reticular roentgenographic pattern, fibrotic changes mainly in subpleural location at CT, lack of lymphocytosis in BAL fluid and histological features of usual interstitial pneumonitis and BOOP in biopsy specimens are all considered risk factors for a fatal outcome.

Adult↗

PubMed1996

[HRCT of the lung in collagenoses].

Collagen vascular diseases, representing systemic soft tissue disorders, may cause a broad spectrum of pathologic changes of the respiratory tract. The type and extent of manifestations can vary considerably among individuals and entities. This survey describes the chest radiographic and, in particular, high-resolution computed tomographic (HRCT) findings of individual lesions of the respiratory tract. It includes fibrosing alveolitis (alveolitis, interstitial pneumonia, pulmonary fibrosis) and bronchial (bronchitis/bronchiolitis, bronchiectasis), pleural and vascular manifestations, as well as lymphadenopathy and abnormalities related to therapy. We present typical patterns of changes in progressive systemic sclerosis (PSS, scleroderma), systemic lupus erythematosus (SLE), mixed connective tissue disease (MCTD, Sharp syndrome), Sjögren syndrome, overlap syndrome and rheumatoid arthritis (RA). Furthermore, we describe findings which are specific for individual entities such as esophageal involvement in PSS, acute pneumonitis and pulmonary hemorrhage in SLE, lymphoproliferative disease in Sjögren syndrome and necrobiotic nodules in RA.

Arthritis, Rheumatoid↗

PubMed1996

Hospital-acquired candida and aspergillus pneumonia--diagnostic approaches and clinical findings.

Bronchoscopy with bronchoalveolar lavage (BAL), collection of bronchial secretions (BS) and/or high resolution computed tomography (CT) of the lungs was performed in 70 patients with candida and/or aspergillus pneumonia. The sensitivity of bronchoscopy in detecting histologically proven fungal disease was 59%. Characteristic CT signs were found in 11 of 14 patients with candida pneumonia and 16 of 19 patients with aspergillosis. The more frequent use of bronchoscopy and CT scans between 1990 and 1992 compared with 1986-1989 for the differential diagnosis of new pulmonary infiltrates in immunocompromised patients resulted in earlier antifungal treatment (14 vs. nine days; P < 0 center dot 025). In the second treatment period survival was improved from 36 to 50% (not significant). Bronchoscopy and high resolution CT scans are mutually complementary diagnostic tools and should be performed as early as possible in the course of pneumonia in patients at high risk of fungal diseases.

Adolescent↗